How Many Days Will You Need AC In WI This Summer?

WISCONSIN — Residents of Wisconsin are running their air conditions more often than in the previous two decades to remain comfortable during hot summer days, according to an interactive map and analysis from The Washington Post.

And it’s only going to get worse, according to projections for 2060. From 1981 to 2000, Wisconsin residents needed their air conditioners an average of 70 days. That increased by five more days from 2001-2022, and is projected to increase by 13 days by 2060.

In Wisconsin, here’s how heat indices and actual air temperatures have changed and are projected to change:

• 1981-2000: 65 summer days requiring air conditioning
• 2001-2022: 70 summer days requiring air conditioning
• Projected for 2060: 83 summer days requiring air conditioning

The analysis is based on the heat index, the feel-like temperature that combines the air temperature and relative humidity, rather than air temperature alone. A 65-degree Fahrenheit daily mean temperature was used to capture cooling needs throughout the day in cities nationwide.

The Post cited 2022 research in setting the 65-degree heat index threshold to determine air conditioning requirements. Any day surpassing that threshold was counted as a day requiring air conditioning for all locations annually, The Post said. The news outlet was assisted in the analysis by Colin Raymond, a UCLA research scientist. For the projected 2060 period, The Post used forecast air temperature and specific humidity from the NASA Center for Climate Simulation.

This year has so far been the hottest summer on record for millions of Americans from California to Maine as heat records fall around the country, especially in the U.S. Southwest as the world grows hotter with more greenhouse gasses added to the atmosphere.

Since record-keeping began, some of the hottest temperatures worldwide have been seen in the last 10 to 15 years. Randall Cerveny, a professor at Arizona State University, told The Associated Press the heat records are the clearest possible signal that humans are altering the climate.

In addition to the U.S. Southwest, Temperatures in India and the Middle East have been exceedingly hot this year, he said.

“It feels like the air is a blanket of just hotness that is enveloping you,” he said of the heat, which killed at least 37 people in the United States in July, CNN reported.

It’s been the hottest summer on record to date for around 100 US cities from Maine to California. Heat is suspected in the deaths of least 37 people in the United States in July, a number experts said is likely underestimated due to the amount of time it takes to attribute a death to heat, nature’s most prolific weather killer.

The Associated Press contributed to this report.